The first test of the National Zoo’s new home for its sea lions was a few days ago. Summer dived in first, scoping out every nook and cranny without hesi­ta­tion. Next was the pup Sophie, who was a bit more cautious. The other two female sea lions went in last. By Day Three, they were acting as if they’d always lived there.

Now comes the bigger test, as the zoo prepares to open its American Trail exhibit to the public Saturday.

The trail, planned and built over five years at a cost of $42 million, brings together several beloved North American species, including California sea lions, gray seals, gray wolves, ravens, pelicans, river otters, beavers and an American bald eagle. It is a combination not often seen at zoos. Many of the species have rebounded after their numbers dwindled, and zoo officials hope the exhibit will help convey a conservation message to their 2 million annual visitors.

The new exhibits are state-of-the-art and replace aging habitats that were cutting edge when they were built during the Carter administration but have since become increasingly difficult and expensive to maintain. Many of the improvements are not visible to visitors but are critical to the welfare of the animals. The sea lions enjoy better filtered water, which is kept clean using ozone instead of chlorine. The new pool doesn’t leak, like the old one did, and it conserves water by recycling it. The sea lions’ new digs also have a wave machine that sends water crashing against huge rocks. The oceanside feel is by design.

“We tried to create a little piece of the West Coast,” said Chuck Fillah, associate director of planning and strategic initiatives. “You might think you’re in Oregon.”

There are three viewing areas: one below water, one partially below water and one above water. Zoo officials hope these vantage points will better accommodate visitors, who sometimes find the newer, bigger, more naturalistic exhibits frustrating because animals can stray out of view.

“We have to balance conservation- science needs against visitor-experience needs against animal-welfare needs,” said Donald Moore, associate director of animal care sciences who is also a North American wildlife specialist and self-identified “bear man.”

The new habitat for the two gray wolves, for example, is up on a hill, offering visitors a clear view. However, in order to make the place more interesting for the inhabitants — or, in zoo lingo, to provide more “enrichment” — zoo officials installed cave-like huts based on wolf dens, a potential source of irritation for snapshot-happy tourists and crestfallen tots.

The humans who come to the zoo will be getting more enrichment, too.

Another major highlight of the American Trail, the Seal Rock Cafe, is purely for them. It will offer sustainable, locally sourced seafood dishes and is part of a larger overhaul by a new contractor, Sodexo, of the zoo’s previously hamburger-and-french-fry-heavy offering. The change was inspired in part by the success of the Mitsitam Cafe at the Smithsonian’s National Museum of the American Indian, which zoo officials said has raised expectations for visitors to all parts of the institution.

With federal funds shrinking, zoo officials need to find other ways to bring in revenue, said spokeswoman Pamela Baker-Masson, and improving amenities for visitors is potentially one of them.

None of the animals along the American Trail is as exotic as Kandula, one of the zoo’s Asian elephants, which strolled by the gray wolves along a fenced-in elephant walk.

“I never get tired of that,” Fillah said, pointing to Kandula.

But the animals are relevant to many of the zoo’s visitors, who are more likely to spot one of the animals while hiking or camping than they are to see an elephant or a giant panda.

“Families come to Washington maybe only once in their lives to see their nation’s capital,” Moore said.

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